Pure piston motion of optically flat micromirrors in a fully programmable micro diffraction grating

We present a fully programmable micro diffraction (F-PMDG) grating in which each micromirror in a 1D array can be individually deflected out-of-plane by up to 1 µm. The maximum operating voltage is <30V and the lowest resonant frequency is >10kHz. The 120 µm wide and 700 µm long mirrors are designed to remain optically flat during actuation. The peak-to-valley curvature of a fully actuated micromirror is shown to be 10 nm equal to a radius of curvature of 7m. Fabrication of the F-PMDG requires only three photolithography masks.